I thought it would be a good idea to document the projects I recently started (but not necessarily completed). Newer ones listed first. Some of the bigger projects might get special in-depth posts of their own (later…)

MPPT is a must & don’t trust eBay listings (if it’s <$50 it’s probably PWM). Otherwise I lose half the power because of the 24V panel and 12V battery mismatch

Raspberry Pi behaving weirdly? Check the power supply

You have to manually activate the bias tee every time you start the RTL-SDR! Otherwise that unpowered LNA is dead weight (spent a few days confused about this, thought the FM bandstop filter was to blame)

BLE Smartwatch reverse engineering – still ongoing. Bought a cheap v-fitness branded smartwatch, thought it would be interesting to do some RE and make my own app so I don’t have to trust the Play Store version which requests a lot of permissions.

Lots of issues with gattacker, choosing a suitable adapter for sniffing and so on

Ended up grabbing a $10 BBC micro:bit off eBay which coupled with this brilliant software makes things workable

More info in another post

Telstra Air WiFi – big idea was to leech off the WiFi from the pink Telstra payphones, essentially giving unlimited internet for $5 (cheapest Telstra data plan was on discount)

$10 15dBi Yagi from eBay – good sector antenna (radome enclosed), picked up a lot of the nearby Telstra Air/Fon WiFi home hotspots (limited to an unbearable 2Mbps)

Underestimated my distance to the nearest payphone (1.6km RF LOS, oops). Plugged the values into a free space path loss calculator and it’s just physically impossible unless I have a point to point link

Turns out the payphones are not fiber connected, speedtest only shows ~8Mbps anyway…

I was scrolling through Gumtree a few weeks back and came across one of the best deals I’ve ever found – someone was selling a DJI Phantom 2 for $50 AUD! Admittedly I’m a bit late to the game (it is ~6 years old) but it was a flagship back in the day, didn’t have any obvious defects and in fact included a H3-3D gimbal, iOSD mini and video transmitter. After confirming with the seller that it does work (besides requiring a battery replacement), I went to pick it up.

the whole package

The provided battery was swollen and unusable but it did have enough juice to power the drone on and play the startup sound. While I waited for a replacement third-party battery ($75AUD after some haggling on eBay), I practiced flying on my Syma X5C clone and read up on the CASA rules.

Upon receiving the battery, I did a quick motor test with the props off, calibrated the compass and went to check if it could do a stable hover, with no problems whatsoever. The first proper flight was in a local park without video footage (I was yet to purchase a camera). I didn’t time it but I would say it flew for around 20 minutes before the auto-land kicked in, which was great.

I found out that the H3-3D gimbal only officially supports the GoPro Hero 3 cameras so I went and bought a used GoPro Hero 3+ Black edition (again ~6 years old!), which supports 4K@15, 2.7K@30 and 1080@60. The default settings were unsatisfactory so I switched it to Protune mode (‘raw’ video), set the min & max ISO to 200 and sharpness to Low, so that I could edit the footage later. Below is a clip of the resulting video (scaled down).

The video was shot over South Pine River in Brisbane, QLD, Australia, at around 7am. I set the max height to 120m using the Assistant software to avoid inadvertently doing something illegal. Luckily winds were light and not many people were out walking. Overall I’m happy with the footage, especially given the lack of a live video feed and me having to bend my neck 90 degrees to fly the thing. Hopefully when I receive the 5.8GHz video receiver I can frame the shots better and minimise the janky movements. But that’s for another day…

Additional notes: TIL that if you don’t want the drone tipping over on landing you shouldn’t use CSC to shut down the motors, instead you should just hold the throttle down for a few seconds.